Method of and apparatus for rolling metal



Nov. 27, l1.934. w. R. CLARK l 1,982,571

METHOD OF AND- APPARATUS FOR ROLLING METAL NOV. 27, 1934.` -W- R CLARK j1,982,571

METHOD OF' AND APPARATUS AFOR ROLLING METAL Filed Feb. 2, 1923ZSheetS-Sheet 2 gig. 5.

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.Patented Nov. 27, 1934 PATENT OFFICE Y METHOD oFl AND APPARATUS Foa iaoLLmG METAL Waitan. cnn-k, nrilzeport, conn.' Applicauon Febgwjyz.192s, smal No. 251,430

4i claims. (cl. soi-41) 'I'his invention relates to a method of andyapparatus for rolling metal, and more especially to a method of and anapparatus for controlling the size of the pass or opening between therolls 5 of a rolling mill in order to maintain an even or uniform gaugein the material delivered by the rolls from end to-end of a given pieceof material or from beginning to end of a series of pieces.

In the rolling of material, particularly of sheet l0 material, itis ofgreat importance that the sheets be of uniform gauge from one side tothe other and from end to end. If the material delivered to the mill isof substantially even gauge from end to end and the rolls of the millare 15. properly shaped to give the minimum degree of variation fromedge to edge that can be maintained in commercial rolling practice, thenthe remaining causes of gauge variation will be found Ato result 'fromvariations in the hardness of the material being rolled or fromvariations in the dimensions or shapes of the rolls of the mill due tochanges in the temperatures of the rolls. The present invention relatesto the prevention of l variations in gauge due to changes in thedimensions of the rolls of the mill, and particularly' such variationsas are produced by the heating of the rolls. v

According to the prior art',- itis the usual practice to provide rollsof fairly large diameter which run slowly `so lthat they may be`maintained at a normal temperature dueto natural air cooling whichcompensates for any heat' that they may absorb during the operation ofrolling. It has also been proposed to use hot or cold air `blasts whichare directed against the faces of the rolls, gas, or electric heaters,or water, or other fluids, which are flowed-over the surfaces of therolls. All of these methods for regulating the temperatures of therollsto maintain these temperatures 40 as nearly as possible to what areconsidered normal working temperatures, involve manual control, andrequire constant attention and considerable skill on the part of themill operator, and while they are, to .a certain extent, effective inthe case of large and slowly moving rolls, they are veryunsatisfactorywhen used with siall rollsrotating at high speed. l

The general bject of the invention is to pro-v vide a method and meansfor controlling the sizeof the pass or opening between the rolls of f arolling mill not only within narrower limits .than heretofore possible,but also without the constant care and attention necessary with knownxmethods andmeans. Another object is to provide a mill in which the sizeof the opening may be adjusted to deliver the required gauge, before themetal begins to pass through the mill, and in which the size of theopening after this adjustment has been made will be kept constantwithout further attention on the vpart o'f the operator. 60

The invention is applicable to either hot or cold rolling.

The invention in a broad aspect contemplates the automatic transfer ofheat from or to the rolls of a mill according to` -whether the tem-'65peratures are' above or` below normal working temperatures, andin a morespecific aspect, the f transfer of heat from or to the frolls by meansof fluids which are directed against the faces or 4.journals of therolls, and the automatic control of the application of these fluids,laccording to the temperature conditions of the rolls, by athermo-.sensitive element or elements which are constantly subjected tothe roll temperatures.

In order to assist in eiectively controlling the temperatures of therolls of the mill, and therefore the size of the pass or opening betweenthe mill rolls, it is desirable to introduce the material to be rolledat a predetermined constant temperature, Accordingly, another object ofthe invention resides in a novel method and means for controlling thetemperature of the material entering the mill.

A further object of the invention is to furnish means for varying theareas of the roll surfaces with which the cooling or heating fluidscomein 4contact in order to more precisely control theeffect of theseiluids on the temperature of the roll.l

To these and other ends the invention consists in the' novel featuresand combinationv of parts tobe hereinafterdescribed and claimed.

In the drawings:

Fig. 1 is a side elevation, partly in section, of

a `two-roll mill showing a preferred form of my 95 temperaturelcontrolling means used in connection therewith;

Fig. 2 is a fragmentary viewA showing one of the elements used to bringthe cooling or heatingl fluids into contact with the roll surfaces;

Fig. 3 is a sectional view along line 3-3 of Fig.

Fig. 4 is a fragmentary view of one of the heat responsive elementsshown in Fig. 1,;

Fig. 5 is a view of a mill roll and a diierent type of element, forbringing the heating or cooling fluids into contact therewlth,'th`anthat shown in ma 1; n J

Fig. 6 is a view similar to Fig. 2 but showing a modification; l

Fig. 7 is a sectional view`^`along line 7-7 of Fig.

6, and Fig. 8 is a somewhat diagrammatic sec--l invention in connectionwith the two-roll metal rolling mill shown in the drawings, which hasbeen chosen for illustrative purposes on account of its simplicity, andit will be understood that the in-` vention is not limited to thisparticular type of mill, nor to any particular roll or rolls of a mill,but may be applied to a roll or rolls in any of the well known types ofmills and is particularly useful in the four-high mills and clustermills generally in use.'

In the drawings, the reference numeral- 4 indicates, in general, theframe of a rolling mill of which only one end is shown and in which aremounted bearings 5 and 6, of rolls 7 and 8, bearing 5 being usually xed,while bearing 6 is adjustable towards and away from bearing 5 by means,such as screw 9, mounted in head 10 of frame 4, and adjusted by means ofhand wheel 11.

The material M enters the mill at A with an initial thickness of T1 andemerges from between the rollswith a nal thickness of T2. The rolls ofthe usual mill at the start of the rolling operation may have thetemperature of the room in which the mill is placed, and the increase intemperature in the rolls may partly be due to the fact that the materialbeing acted on enters the mill at a higher temperature than the roomtemperature, resulting from the material having been heated; forexample, by being previously acted on by another mill, or from theeffects of annealing the material. To this is added the heat due toovercoming internal molecular friction during the act of rolling andheat due to the surface friction between the rolls and material at allpoints in the passage of the material between the rolls where thesurfaces of the material and rolls-move at different speeds and heat dueto friction of the roll necks in their journals. It will be readilyunderstood that as the rolls heat up they expand or increase indiameter, causing a decrease in the bite or amount of clearance betweenthe rolls and thus a decreased thickness or gauge of the materialpassing therebetween. This expansion of the rolls is apt to be greaterwhere the rolls contact with the material than at points more remotetherefrom, and accordingly the contours of the rolls vary as theirtemperatures vary.

In the present invention, the control of the roll temperatures, andtherefore roll contours and gauge variations, is effected by providingmeans for transferring heat from a roll or rolls when the temperaturesthereof are above a predetermined amount, and transferring heat to theroll or 'rolls when the temperatures thereof are below thispredetermined amount, and the transfer of the.

heat from or to the rolls is controlled by means which is sensitive tochanges in the temperatures of the rolls. In the preferred formdisclosed herein, the transfer of heat is brought about by bringing hotor cold fluids into contact with the faces of the rolls, according towhether the rolls are to be heated or cooled, and the application ofthese fluids is controlled by a thermo-sensitive element which respondsto changes in the temperatures of the rolls.

A suitable apparatus for the purpose in viewV may involve a hollowbox-like element 12,` in contact with the face of roll 8, closelyadjacent the point where the material emerges from between f rolls 7 and8, and having an inlet 13 and an outlet 14 for cooling fluid, thepassage of which to box 12 is controlled by balanced valve 15in valvecasing 16 havlngconnected thereto a fluid supply pipe 17. Box 12 is openon the side adjacent roll 8 so that the cooling uid may come intocontact with the face of the roll, and is provided with longitudinalwalls 18 and 19, which extend radially from the face of the roll 8, andan outer Wall 20 which is concentric to roll 8 and which, in thedrawings, is shown formed integrally with wall 18 and end walls 21 and22. Wall 19 is received between the end walls 21 and 22 andadjustablysupported on wall 20 by means of flange 23, bolts 24 beingprovided which pass through ange 23 and wall 28, in order to secure wall19 in various positions of adjustment, wall 20 being provided with slots25 through which the bolts 24 pass and which permit the adjustmentbellows 26 is provided,'connected to valve 15 by means of yoke 27 andvalve stem 28, valve 15 being constantly urged into closed position bymeans of weight 29, adjustably mounted on the outer end of lever 30, thelatter having a fulcrum. point at 31 on lever 32, which is pivoted at 33to frame 34, the opposite end of lever 30 engaging knife edge 35`on yoke27. The thermostatic bellows 26 is secured to the upper end of frame 34,the lower end of the latter being mounted in any desired manner on valvecasing 16.

Adjacent the surface of roll 8, and beyond box 12 in the direction ofrotation of this roll, is a bulb 36 containing a thermo-sensitive fluid,bulb .36 being connected to thermostatic bellows 26 by means of pipe 37which enters bulb 36 and terminates interiorly of bulb 36 near thebottom thereof. The thermo-sensitive fluid may consist of alcohol, ethylether or alcohol mixed with water, depending on the temperature rangethrough which the regulator is to be sensitive. Bulb 36 is partiallysurrounded by casing 38 formed of heat insulating material, casing 38having an 120 open side directed toward roll 8 and being supported in oron the mill in any desired manner. 'I'he bulb 36 is surrounded in alldirections, except in the direction of roll 8, by means of casing 38 sothat the thermo-sensitive fluid is acted 125 on by the heat of the rollbut substantially unaffected by outside temperature conditions. In thepreferred form shown, the bulb-36 is not di-l rectly in contact with theroll 8 but is spaced outwardly therefrom a short distance in order thatit may not be affected by heat which 'would otherwise be generatedthrough friction between these parts. l u

The operation of the device will be readily understood from the above`description 'but will nowv be briefly described. Assuming that theseveral parts are in the position shown in Fig. 1, and that thetemperature of roll 8 has risen above the 'normal working temperature,the excessive heat in roll 8 acting on the thermo-sensitive fluid 140 inbulb 36 causes this fluid to vaporize or expand, exerting pressure onthermostatic bellows 26 through pipe37. The pressure exerted onthermostatic bellows 26 causes the latter to expand, against theconstant pressure of weight 29 145 acting through lever 30, forcing yoke27 and valve stem 28 downwardly, opening valve 15 and permitting coolingfluid to pass from pipe 17, through valve casing 16, into box 12, whereit comes into contact with roll 8 and finally flows 150 out through pipe14. Roll 8 will now start to' cool and as soon as this occursthe bulb 36and the-thermofsensitive fluid therein likewise cool,

finally causing the condensation of the vapor and A29 on lever 30, andthe thermostatic belows contracts, closing valve 15, and stopping theflow of the cooling fluid. The provision of adjustable wall 19 in box 12permits the cooling fluid to be brought into contact with a variableamount or particular portion of the roll surface in order to moreclosely control the effect ofthe cooling fluid on the roll. By adjusting-weight 29 on lever 30v the valve 15 can be caused to open at a lower orhigher temperature, as will be understood.

In certain cases, it may be desirable to control the temperatureof thematerial entering the mill in order to insure that the material entersthe mill ata constant predetermined temperature., A suitable means tothis end may be provided by pipe 39, having a series -oi! nozzles 40through which heating or cooling fluids may be directed against thematerial M before it enters the mill.

The application of these fluids to the material may be controlled inmuch the same manner as in the case of the uid which ows through -box 12to roll 8, and may be briefly described as being controlled by valve 41,connected to the thermostatic bellows 42, which is connected by pipe 43,to bulb 44 containing a suitable thermo-sensitive liquid such as one ofthose mentioned above.,-

Bulb 44 is mounted in any suitable manner closely adjacent to butseparated from the lower face of material M, and surrounded on allsides,- exceptdn the direction of material M, by means of casing 45formed of heat insulating material. If desired, trough 46 may beprovided to collect they iiuids after they have acted on material M, thefluids being carried away from the mill by pipe 47.

Up to this point in the description of my invention, I`have beenconcerned with excessive temperatures which tend to expand the rolls ofthe lmill and to cause decreased thickness in the material passingthrough the mill. It will be evident, however, that in case the millrolls cool below their normal working temperatures they' will contract,bringing about an increase in the size ofthe opening or pass between therolls and increased thickness of the material which may thereafter passthrough the mill until such a time as the rolls may regain their normaltemperatures. Thel cooling of the mill rolls may occur through the millstanding idle during the night or during intervals when material is notpassing between the rolls. Various .attempts 4have been made to takecare of this jondition, it being a common expedient to provide anelectricallyheated jacket which .is placed about the mill roll or rollsduring the idle periods, but this manner Voi? maintaining temperatures,as well as other expedients which have been proposed, is not veryeffective and requires skill and constant care and attention on the partof the mill operator.

According to this invention, it is proposed to control decreases in rolltemperatures by transferring heat automatically to the roll or rolls ofthe mill when the temperatures thereof are below normal, and thistransfer of heat is controlled by means whichl is sensitive to changesin the roll temperatures.

In carrying out this part of my invention, I provide a box-like element48 for the heating medium, this element being substantially similar tobox 12 and in contact with roll 8 closely adjacent the point where thematerial M enters between the rolls vof the mill. Box 48 is providedwith an inlet 49 and an outlet 50, the passage of the heating iiuid,'orother medium, being controlled by balanced valve 51, in valve casing 52,having connected thereto supply pipe 53. Connected to valve 51, by meansof valve stem 54 and yoke 55, is a thermostatic bellows 56, mount-l edon frame 57, secured in any desired manner to valve casing 52; andconnected to the interior of thermostatic bellows 56, is a'pipe 65,leading to bulb 58, containing a suitable thermo-sensitive uid, as forexample one Vof those mentioned above, the bulb 58 being spaced slightlyfrom the roll 8 and surrounded on all sides, ,except in the directionofroll 8, by means of casing 59 of heat `vinsulating material. 'I'hepipe 65 enters bulb 58 and terminates interiorly near -the bottomthereof. It is to be noted that in this case the expansion of thethermo-sensitive fluid in bulb 58, when the temperature of the roll isnormal, or above normal, acting through pipe 65, on thermostatic bellows56, closes valve 51, so that the latter permits heating fluid to flowinto box 48 only when the roll temperature, and therefore the pressureon the fluid, is lower thani normal. As a suitable means for opening thevalve 51 when the thermo-sensitive fluid condenses or contracts duringthe periods when the roll temperature. may be sub-normal, there isprovided a lever 60 having one end in contact with knife-edge 61 onyoke` 55 having an adjustable weight 62 on its outer end and anintermediate fulcrum point at 63 on lever 64, the latter being pivotallysupported on frame 57.. When the mill is in operation, the

normal temperature of the roll 8 expands or vaporizes thethermo-sensitive fluid in bulb 58 suiliciently so that the pressureexerted thereby acting on thermostatic bellows 56, and against weight y62, keeps valve 51 closed and prevents the now ,of hot fluid to box 48.,When the temperature roll surface to heat the same, and then flows outthrough outlet 50.

, In Fig. 5 I have shown a different type of element for bringing theheat transferring fluids into contact with the roll surfaces in whichthe boxes are replaced by a longitudinally extending pipe 66 havingmounted thereon closely adjacentA the roll 67 a series of nozzles 68,each controlled by an individual valve 69, and the flow of fluid to pipe66 being controlled by a main valve 70 which may be similar to valves 15and 51 and 135 controlled in much the same manner. The nozzles 68 andvalves 69 may be of any preferred type and are not shown herein indetail. with this form, the amount of heat transferring fluid broughtinto contact with the roll surface or the particular portion thereof tobe heated or cooled may be varied by adjusting the individual valvescontrolling the flow of fluid through the nozzles, and in certain-cases,especially where a narrow strip of material is being rolled, theapplication of heat transferring fluids to the ends of the roll may bedispensed with altogether by closing the valves at the ends of the pipe66.

`In Figs. 6 and 7 I have shown a box-like yelement somewhat similar tothat shown in Fig. 2

l 1y extending walls 76 and '77, which are integrally formed withrespect to walls 74 and 75, and provided with slots 78 and 79 throughwhich pass suitable securing means herein shown as bolts 80 and 81.

In the preferred form, the box-like or other element for bringing theheating fluid into contact with the surface of the roll is mounted in aposition closely adjacent the point where the material enters betweenthe rolls of the mill, in order that the heat may be transferred to apart of the roll surface immediately before such part engages thematerial, while the cooling box or other means for bringing the coolingfluid into contact with the roll is mounted closely adjacent the pointwhere the material emerges from between the rolls, in order that theexcessive heat may be carried away before it has an opportunity topenetrate into the interior -of the roll to any great extent. Thethermo-sensitive elements are mounted in contact with the roll surfacebetween the cooling and heating boxes, although this arrangement may bevaried to a considerable extent. For instance, in certain cases, it maybe found desirable to place the thermo-sensitive element for controllingthe heating fluid in a position closely adjacentthe point where thematerial enters between the rolls in order that it may be controlled bythetemperature of theroll immediately preceding the engagement of theroll with the material.

In Fig. 8 I have shown apparatus of the kind y described in connectionwith Fig. l, applied to the lower roll of a mill as well as the upperroll.

The apparatus described herein is capable of maintaining rolltemperatures within very narrow limits owing to the flexibility of thecontrolling means. The weights acting on the thermostatic bellows areadjustable, so that the thermostatic bellows may be brought intooperation at various pressures corresponding to different ternperaturesof the rolls, while the adjustability of the cooling and heating'boxesprovides a ready means for controlling the effect of these fluids on therolls.

Although I have shown and described herein a particular form ofthermo-sensitive element, it will be readily understood that the valvescontrolling the transfer of heat from and to the rolls may be controlledby other forms of thermostats.

It will be further understood from the foregoing description of theinvention and its mode of operation that my improved method andapparatus, while particularly desirable in controlling the temperaturesof the rolls of a rolling mill, is not limited thereto, but may beapplied to various situations where it is important to maintain constanttemperatures.

While I have shown and described some preferred embodiments of myinvention, it will be understood that the same is not limited to theexact details shown but is capable of many modifications and variationswhich will lie Within the spirit of the invention and the scope of theappended claims.

I claim: x

l. In a rolling mill for metal, the combination of a pair of rotatablerolls between which the metal passes, and means for controlling the sizeof the pass between the rolls to produce uniform gauges in the metal,comprising means associated with at least one of said rolls adapted totransfer heat thereto when the temperature of the roll drops below apredetermined normal temperature, and a thermo-sensitive elementassociated with the roll surface and subjected to the temperaturechanges in the latter, said thermo-sensitive element controlling theflow of heat to said roll through said heat transferring means.

2. In a rolling mill for metaL. the combination of a pair of rotatablerolls between which the metal passes, and means for. controlling thesize of the pass between the rolls to produce uniform gauges in themetal, comprising means associated with at least one of the rolls at thesurface thereof adapted to transfer heat thereto when the temperature ofthe roll drops below a predetermined normal temperature, and athermo-sensitive element associated with the roll surface and subjectedto the temperature changes in the latter, said thermo-sensitive elementcontrolling the flow of heat to said roll through said heat transferringmeans.

3. In a rolling mill for metal, the combination of a pair of rotatablerolls between which the metal passes, and means for controlling the sizeof the passA between the rolls to produce uniform gauges in the metal,comprising means for bringing a cooling fluid into contact withtheworking surface of at least one of the rolls, a thermo-sensi' tiveelement associated with said. rollvand subjected to the temperaturechanges at the working surface of the latter, and a connection betweensaid thermo-sensitive element and said means for bringing a coolingv uidinto contact with said roll, whereby the ow of the fluid is controlledby said thermo-sensitive element.

4. In a rolling mill for metal, the combination of a pair of rotatablerolls between which' the metal passes, and means for controlling thesize of the pass between the rolls to produce uniform gauges in themetal, comprising means for bringing a heating fluid into contact withthe working surface of at least one of the rolls at one pointcircumferentially thereof, a thermo-sensitive element associated withthe roll surface at another point circumferentially thereof andsubjected to the temperature changes in the latter, and a connectionbetween said thermo-sensitive element and said means for bringing aheating fluid into contact with said roll, whereby the iiow of the fluidis controlled by said thermo-sensitive element.

5. In a rolling mill for metal, the combination of a pair of rotatablerolls between which the metal passes, and means for controlling the sizeof the pass between the rolls to produce uniform gauges in the metal,comprising means for bringing heating and means for bringing coolingfluids into contact with at least one of said rolls according to thevariations in the temperature of the roll below or above the normalworking temperature' of the roll, and means associated with said rolland actuated by changes in the temperature conditions in a limitedportion of the roll for controlling the iiow of cooling and heatingfluids.

l 1,9e2,571 6. In a rolling mill for metal, the combinationy aturechanges in the latter, said thermo-sensitive element controlling theflow of heat throughsaid heat transferring means.

7. In a rolling mill for metal, the combination of a pair of rotatablerolls between which the metal passes, and means for controlling the sizeof the pass between the rolls to produce uniform gauges in the metal,comprising means associated with at least one of said rolls adapted totransfer heat therefrom when the temperature of the roll rises above apredetermined amount, said means including means for varying the size ofthe zone from which the heat is transferred, and a thermosensitiveelement associated withv said roll within said zone and subjected to thetemperature changes in the latter, said'thermo-sensitive ele` mentcontrolling the flow of heat from said roll through said heattransferring means.

8. .In an apparatus for controlling the texn-y perature of a roll of arolling mill for strips of metal or the like, means associated with saidroll adapted to transfer heat therefrom when the temperature of the rollrisesvabove a predetermined amount, said' means 'including means yforvarying thes'ize of the zone from which the heat is transferred, and athermo-sensitive element associated with said roll and subjected to thetemperature changes in that Iportion of the latter which contacts withthe strip, said thermosensitive element controlling the flow of heatfrom said roll through 'said heat transferring means.

, ature conditions in the latter.

10. The method of controlling the gauge of material delivered by therolls of a rolling mill, which comprises delivering the material to themill at a constant predetermined temperature,

transferring heat from a roll of the mill when the temperature thereof-rises above a predetermined temperature, and controlling the transferof heat from the roll by the temperature conditions at the surface ofthe roll.

11. The method of controlling the gauge of material delivered by therolls of arolling mill, which comprises delivering the` material tow themill at a constant predetermined temperature, transferring heat to aroll of the mill when the temperature at the surface thereof drops belowa predetermined temperature, and controlling the transfer of heat by thetemperature conditions at the roll surface.

12. 'I'he method of controlling the gauge of transferring heat fromorto'the rolls according to whether the temperature conditions at thesurfaces of the latter are above orbelow predetermined temperatures, andcontrolling the transfer of heat by the surface temperature conditionsin the rolls. e

13. The combination with the rolls of a sheet mill, of a devicecontacting the roll surface responding to changes of. roll temperatureduring rolling,` and heat transfer apparatus controlled by said deviceto control local variations in the mined portions of the roll surface,said thermo-x sensitive element controlling the transfer of heat throughthe heat transferring elements to control the roll contours.

15.,In an apparatus for controlling the temperature of a roll of arolling mill .for a' strip of metal or the like, means for bringingheating and means for bringing cooling fluids into contact with saidroll, means associated with said roll for controlling the flow ofcooling and heating uids, said means being actuated by changes in thetemperature conditions in that portion of the roll which contacts withthe 'material operated on, and means for varying the'areas of the rollsurface with which the heating and cooling fluids come into contact. v

16.v 'I'he combination with the rolls of a sheet mill, of a deviceassociated/with at least one of said rolls and in contact with themetal-engaging roll surface which is responsive to changes of ing theroll temperature so as to maintain the roll bite within certaindimensional limits during rolling and thereby control the gauge.

17. The combination with the rolls of a strip mill, of devices adjacentthe metal-contacting roll surfaces responding to changes of rolltemperature during rolling, heat transfer devices'for varying the rollsurface temperature in both directions by transfer of heat to and fromthe roll, and operative means of connection between said heat transferdevices and said temperature-responsive devices for controlling saidheat transfer 4devices automatically.

18. The combination with the rolls of a strip mill, of devicesresponding to changes of roll temperature during rolling, located inproximity to the surface of at least one of said rolls and disposed atdifferent points on said roll, apparatus for varying the surfacetemperature of said roll by transfer of heat to and from the rollthrough a fluid applied to the roll face, and operative `means ofconnection between said heat transfer apparatus and saidtemperature-responsive devices for controlling automatically the gaugebeing rolled.

19. The combination with the. rolls of a strip mill, of means respondingto changes of roll surface temperature during rolling, a source of rollheating fluid, a source of roll cooling fluid, and heat transferapparatus associated with said fluid sources and controlled by saidtemperature-responsive m'eansfor heating at least one of said rolls bythe application of heating fluid to its face when the roll'temperaturefalls below a predetermined limit, and for cooling said roll by theapplicationof cooling uid to its face when the 150 temperature of theroll rises beyond a predetermined limit. y Y i 20. In a mill for rollingmetal, the combination with a pair of metal reducing rolls having a bitethrough which the material passes, of automatic mechanism forcounteracting temperature changes in the rolls to maintain the bite at apredetermined size, including devices for applying hothand cold fluidsexteriorly to at least one of the rolls as required by changes in therolling conditions, and thermo-responsive means adjacent themetal-contacting roll surfaces for automatically controlling theapplication of said fluids to said roll.

21. The combination with a strip mill, of devices associated with saidmill adjacent the metalcontacting roll surfaces which are responsive tochanges of roll temperature during rolling, a heat transfer devicecontrolled by one of said first-named devices for decreasing the rolltemperature when it rises above a predetermined limit, and a heattransfer device controlled by the other of said rst-named devices forincreasing the temperature of the roll automatically when it falls belowa predetermined limit, said devices acting in cooperation with eachother automatically to maintain the material being rolled at asubstantially uniform gauge.

22. Means for controlling the gauge of strip metal as the same isrolled, comprising, in combination with the rolls of a strip mill, adevice for changing the surface temperature of at least one of the rollsby transfer of heat through a fluid medium applied to the roll face, athermoresponsive device in proximity to the surface of the roll at onepoint in the periphery thereof and located in line with the metal strippassing through the mill, and an'operative connection between saidthermo-responsive device and said heat transfer device for effecting achange in the roll temperature automatically through the heat transferdevice when the gauge of the material being rolled tends to vary.

23. The combination, with a strip mill, of means for setting the rollsof said mill ,at .a bite of given size, means for decreasing the size ofthe roll bite by the application of Aa heating medium to at least one ofthe rolls, means for increasing the size of the roll bite by theapplication of a cooling medium to at least one of the rolls, and meansresponsive to surface temperature changes of the rolls for controllingsaid bite size changing means automatically so as to maintain the bitesize within predetermined limits.

24. 'I'he combination with a rolling mill, of apparatus associated withthe rolls to vary the temperature of at least one of the rolls in asense tending to reestablish the initial size of the pass as thetemperature of said roll rises or-falls beyond a predetermined limit,and roll surface ,contacting means responsive to changes of rolltemperature during rolling to control the` operation of said apparatusautomatically.

25. The combination with a rolling mill, of apparatus associated withthe rolls to vary the temperature of at least one of the rolls by theapplication of a heating uid or a cooling fluid to the exterior toreestablish the initial size of the pass as the temperature of said rollrises or falls beyond a predetermined limit, and means adjacent ametal-contacting roll surface responsive to changes of roll temperatureduring rolling to control the operation of said apparatus automatically.

26. 'I'he combination with a rolling mill, of apparatus associated withthe rolls to vary the temperature of at least one of the rolls in asense tending to\reestablish the initial size of the pass as thetemperature of said roll rises or falls beyond a predetermined limit,roll face contacting means responsive to changes of roll temperatureduring rolling to control the operation of said apparatus automatically,and means for adjusting the length of that portion of the roll whosetemperature is varied by said apparatus.

27. In a rolling mill for metal, the combination of a pair ofrotatable'rolls between which the metal passes, and means forcontrolling the size of the pass between the rolls to produce uniformgauges in the metal, comprising a heat-transferring element associatedwith at least on'e of said rolls at the surface thereof, and athermo-sensitive element associated with said roll and sub- Jected tothe temperature changes of the latter at the working surface thereof,said thermo-sensitive element controlling the flow of heat through saidheat-transferring element.

. 28. 'Ihe combination with a rolling mill, of apparatus associated withthe rolls to vary the temperature of at least one of the rolls in asense tending to reestablish the initial size of the pass as thetemperature of said roll rises or :falls beyond a predetermined limit,and means adjacent the metal-contactingusurface of a roll responsive tochanges of roll temperature during rolling to control the operation ofsaid apparatus automatically, said apparatus being adjustable to varythe heat of the roll at different points in the length thereof.

29. In combination with a rolling mill for rolling metal and havingsolid rolls therein, means for applying al heating agent externally tothe longitudinally central portion of the rolls, means for applying acooling agent externally to the longitudinally central portion of therolls, valve means controlling the heating and cooling means.-thermostatic means controlling the valve means, and thermal bulb meansheld adjacent the working surfaces of the rolls and operating thethermostatic means.

30. In combination with a rolling mill for rolling metal and havingsolid rolls therein, means for v applying a heating medium to the outerworking surfaces of the rolls, means for applying a cooling medium tothe outer working surfaces of the rolls, and means controlled by Athetemperature of the outerworking surfaces of the rolls for operating themeans for applying heating and cooling mediums.

31. -In combination with a rolling mill for rollm ing metal and havingsolid rolls therein, means controlled by the temperature of the outerworking surfaces of 4the rolls for applying a heating agent to saidworking surfaces whenthe temperature of the working surfaces drops to apredetermined temperature, and i'or applying a cooling agent to theouter surfaces when their temperature rises to a predeterminedtemperature.

32. In combination with a rolling mill for rolling metal and havingsolid rolls therein, means o for applying a heating medium to the outerworking surfaces of the rolls, valve means controlling for applying aheating medium to the outer working metal and having ing surfaces of therolls, valve means controlling"4 said heating means, means for applyinga cooling medium to the outer working surfaces of the rolls,

valve means controlling said cooling means, and

thermostat means controlled by the temperature of the outer workingsurfaces of the'rolls for controlling the valve means.

34. In combination with a rollingmill for rolling metal and having solidrolls therein, means for applying a cooling medium to the outer workingsurfaces of the rolls, and means controlled by the temperature of theouterworking surfaces of` the rolls for operating the means for applyingthe cooling medium. v

. 35. In combination with a rolling mill for rolling metal and havingsolid rolls therein, means for applying a heating medium to the outerworking surfaces of the rolls, and means controlled by the temperatureof the outer working surfaces of the rolls for operating the means forapplying the heating medium.

36. Invcombination with a rolling mill for rolling metal and havingsolid rolls therein, means for applying a heating. agent externally to`the longitudinally central portion of one of the rolls,-

a valve controlling the heating means, means for applying a coolingagent externally to the longitudinally central portion of one of therolls, a valve controlling the cooling means, thermostatic meanscontrolling the valves, thermal bulb means operating the thermostaticmeans,- and means holding the thermal bulb means in contact with theouter surface of one of the rolls.

37. In combination with a` rolling millfor rollsolid rolls therein,means for applying a heating medium to `the outer working surface ofone'of the rolls, means forapplyinga cooling medium to the outer workingsurface of one of the rolls, valve means controlling said heating andcooling means, and thermostatic means controlled by the temperature ofthe outer working surfaces of the rolls for controlling theabove-mentioned valve means.

38. In combination with a mill for c oid rolling of metal having a pairof rolls, means for applying a heating fluid to the outerjworkingsurfaces of the rolls, means for applying a cooling fluid to the outerworking surfaces of the rolls, valve means controlling saidfluid-applying means, and thermostatic means controlled. by thetemperature .of

lthe outer working surfaces of therolls for controlling theabove-mentioned valve means.

39. In combination with a mill for cold rolling of metal having a pairof rolls therein, means for applying a heating fluid to the outerworking sur- 'faces of the rolls, and means controlled by thetemperature of the outer working surfaces of the rolls for operating thefluid-applying means.

40. In combination with a mill for rolling metal having a pair of rollstherein, meansfor applying' a heat transfer medium to the materialentering said rolls, and means subject to the temperature of saidmaterial for controlling the application of such medium.

4l. In combination with a mill for rolling metal `operation when thetemperature of said roll falls surface temperature for operating theabovehaving a pair of rolls therein, means for applying a heat transferiiuid to the material entering said rolls, and means subject to thetemperature of said material for controlling the application of suchfluid. 1

42. The combination with a rolling mill of apparatus associated with therolls to vary the temperature of at least one of the rolls in a sensetending to reestablish the initial size of the pass as the temperatureof said rolls passes a predetermined limit, and means adjacent a rollworking surface responsive to changes of roll surface temperature duringrolling to control the operation of said apparatus automatically.

43. In combination with a rollin mill for cold 'rolling metal and havingsolid rolls therein, means for supplying heat to the outer lworkingsurface of one of the rolls, and means adjacent the metalf contactingroll surface for setting said means in below a predetermlnedlimit.

44. In combination with a rolling mill for rolling metal and havingsolid rolls therein, means yfor applying a cooling medium to the outerworking surfaces of the rolls, means controlled by the temperature ofthe outer working surfaces of the rolls for loperating the means forapplying the cooling medium, and means for varying the area of the rollsto which the cooling medium is applied.

45. In combination with a rolling mill for noliing metal and havingsolid rolls therein, means for applying a heating medium tothe outerworking surfaces of the rolls, means controlled by the temperature ofthe outer working surfaces ofthe rolls for operating the means forapplying the heating medium, and means for varying the area of the rollsto which the heating medium is applied. 46. In combination w'th arolling mill for rolling metal and having solid rolls therein, means forapplying a heating medium to the outer working surface of one of therolls, means for applying a cooling medium to the outer working surfaceof one of the rolls, valve means controlling said heating and coolingmeans, thermostatic means controlled by the temperature of the outerworking roll surface for controlling the above-mentioned valve means,and means for adjusting the length of that portion of the roll surfaceaffected by the heating and cooling mediumsj 47. In a rolling mill forthe rolling of sheets by a cold process, and in combination with one ofthe rolls of said mill, means for applying a body of heating fluid tothe outerworking surface of the roll, means for applying a body ofcooling nuid to the outer working surface of the roll, valve meanscontrolling said duid-applying means, thermostatic means controlled bythe roll working mentioned valve means automatically so as4k to maintainthe roll bite within predetermined dlmensional limits, and. adjustablemeans for varying the length of roll surfaceaffected by the heating andcooling fluids.

WALTER R. CLARK. Y

